Toroidal Remote Plasma Source for Low-Power NF3 Dissociation
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Solution Overview
Problem
Existing remote plasma systems for semiconductor deposition have low gas utilization efficiency and require high power for efficient gas breakdown, leading to costly and wasteful NF3 consumption.
Innovation Solution
A toroidal remote plasma source with plasma legs connected by corner connectors, each comprising a conductive shell, magnetic layer, and primary coil, allowing for improved gas utilization and lower power requirements by focusing RF energy to a smaller volume, enhancing power density and dissociation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional remote plasma systems are used for chamber cleaning, then plasma generation is achieved, but gas utilization efficiency is low and power consumption is high
Solution Approach 1:
The plasma source is divided into multiple discrete plasma legs (typically 4-6 legs) arranged in a toroidal configuration. Each leg contains its own RF coil and magnetic confinement structure, allowing independent plasma generation and optimization. This segmentation enables better control of plasma density and improves gas utilization efficiency compared to a single large plasma volume.
Solution Approach 2:
The system changes the physical parameters of plasma generation by using high-frequency RF fields (e.g., 13.56 MHz) combined with specific magnetic field configurations. By adjusting RF power, gas flow rates, and magnetic field strength, the system achieves high plasma density at lower overall power consumption, directly addressing the contradiction between power efficiency and productivity.
2Reliability
If high power is applied to achieve efficient gas breakdown, then plasma generation is improved, but NF3 consumption increases and becomes wasteful
Solution Approach 1:
Each plasma leg creates a localized region of high plasma density with optimized gas breakdown. The magnetic confinement in each leg ensures that the plasma is generated efficiently in a controlled volume, improving the reliability of plasma generation while minimizing the total amount of NF3 required compared to a distributed low-density plasma approach.
Solution Approach 2:
The toroidal configuration with multiple plasma legs creates a continuous plasma region around the chamber, ensuring consistent and reliable plasma generation. This continuous action maintains effective cleaning without requiring excessive NF3 flow rates, as the plasma is sustained efficiently throughout the entire toroidal path.
3Manufacturing precision
If high flow rates of NF3 are used for remote plasma clean, then cleaning effectiveness is maintained, but process cost increases
Solution Approach 1:
The system dynamically optimizes the balance between NF3 flow rate and RF power by using pulsed or modulated plasma generation in each leg. This dynamic control allows the system to maintain cleaning effectiveness through high instantaneous plasma density while using lower average gas flow rates, reducing the quantity of NF3 consumed.
Solution Approach 2:
The plasma legs use composite structures combining conductive materials, magnetic materials (such as ferrite), and insulating materials to create efficient plasma confinement. This composite design enhances plasma generation efficiency, allowing effective cleaning at lower NF3 flow rates by maximizing the utilization of each gas molecule that enters the plasma region.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The toroidal design achieves higher gas utilization efficiency, reduces power consumption, and lowers gas flow rates, resulting in a more efficient and cost-effective plasma cleaning process.
Implementation Method 1
a magnetic layer around the conductive shell, and a primary coil in the magnetic layer
Implementation Method 2
allowing for improved gas utilization and lower power requirements by focusing RF energy to a smaller volume, enhancing power density and dissociation efficiency
Implementation Method 3
the NF3 is broken down in the plasma to generate atomic fluorine
Data Source
AI summary
Embodiments disclosed herein include a plasma source. In an embodiment, the plasma source includes a plurality of plasma legs connected to each other by corner connectors. In an embodiment, each plasma leg comprises a conductive shell, a magnetic layer around the conductive shell, and a primary coil in the magnetic layer.